Telephone-exchange.



PATENTED MAY 7, 1907.

N. E. uo sTRoM. TELEPHONE EXCHANGE.

APPLICATION FILED APR. 6, 19 01.

3 SHEETS-SHEET 1.

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A TTORNE).

'Wl-T/VESSES 1N5 Namws PETERS co. WASHINCYON, D. C

PATENTED MAY 7, 1907. N. E. NORSTROM.

TELEPHONE EXCHANGE.

APPLICATION FILED APR. 6, 1901.

3 SHEETS-SHEET 2.

/NVN70R E md, BY

ATTORNEY THh NOR/INS PETERS c WASHINGTON, n. c,

No. 852,675. PATENT-ED MAY '7, 1907. E.- NORSTROM.

. TELEPHONE. EXCHANGE.

APPLICATION FILED APR. 6, 1901.

3 SHEETS-BHBBT 3.

W/TNESSESI //VVENT0/? M 7L 8?? I IINITED STATES PATENT OFFIDE.

NILS EMEL NORSTROM, OF CHICAGO, ILLINOIS, ASSIGNOR, BY DIRECT AND MESNEASSIGNMENTS, TO JOHN ANDERSON, OF SALINA, KANSAS, M. E. RICHARDSON, OFSTERLING, KANSAS, AND JOHN II. MARTIN AND H.

KEATING.

TELEPHONE-EXCHANGE.

Specification of Letters Patent.

Patented May 7, 1907.

Application filed April 6, 1901. Serial No. 54,594.

To It w/wm it may concern.-

Be it known that I, NrLs EMEL NoRsrRoM, a citizen of the United StatesofAmerica, and a resident of Chicago, county of Cook, and State ofIllinois, have invented certain new and useful Improvements in Telephone-Exchanges, of which the following is a specification.

My invention relates to telephone exchanges and has for its object thearrange-- ment of devices for use where-a number of local stations areconnected by a party line to a central station.

In calling any particular subscriber or subscribers in a elective partyline exchanges which lays claim to simplicity and rapidity of operationand to locking out subscribers not wanted, it is necessary that at leasttwo operations be performed at the station or stations called. One ofthese operations consists in selecting a desired station from amongthose not desired, and the other consists in connecting the selectedstation telephonically to the party line. In party line exchanges asordinarily made, one of these operations must be performed by thesubscriber himself. Thus, the operator at the central oilice performscertain operations by which she selects a station wanted. She thensignals that station and waits for the subscriber to reply before. shecan complete the operations which will connect the called subscribertelephonically to the party line to the exclusion of subscribers notwanted. If the called and calling stations are both on the same line andif the called station is the first of the two selected, which is thecase in about one-half of all such calls, the operator then has toproceed to call the second station after having waited for the calledstation to answer. Processes of this kind not only waste the time of theoperator, who would naturally be busy in a central office from whichemerge many party lines, but they divide the actual control of the linebetween the operator and the subscriber. Where control of the line isdivided in this way it is possible for inquisitive subscribers,

by taking advantage ofcertain particulartimes during a callingoperation, to remove their receivers from their hooks and thus becometelephonically connected to the party line in opposition to the wishesof the operator and other subscribers.

' The present invention is distinguished from prior exchanges in thatthe connection of one or more subscribers to the party line is in no waydependent upon operations per formed by the subscribers themselves, andthere is no occasion for the operator to wait for an answer beforecompleting a call. By a continuous operation involving very little time,she selects and connects the desired stations. She then signals thestations and proceeds with other business without waiting 0 5 for areply. Subscribers not called are definitely cut out or excluded fromtelephonic connection with the line, because at their stations there areopen connections, the open or closed condition of which is not involved,either directly or indirectly, with any operations performed by thesubscribers.

In the accompanying drawings Figure 1 is a diagram illustrating at itsleft hand side the central office apparatus and electrical 7 5connections, and illustrating at its right hand side a local stationmarked No. 1. Fig. 2 is a diagram of two additional local stationsmarked respectively No. 2 and No. 3. Fig. 3 is a plan of the selectingswitch shown in the So diagram of Fig. 1. Fig. 4 is a section on line 44of Fig. 3, the contact maker also being shown in section. Fig. 5 is asimilar section with the contact maker at a slightly different position.Fig. 6 is a section on line 6-6 of Figs. 3 and 4.

In the said drawings N represents a plate of insulation on which ismounted the apparatus constituting the selecting switch. A contact makerP having an extension P and 0 secured to the plate N by the pivot P ismovable between a contact making stop 76 and another stop P. On theouter edge of the plate N is a segment of a dial N marked with thefigures 1, 2, 3 etc up to 9. Also on 9 5 the plate are a series of pinsN so located -with respect to the numbers on the dial that shapedbracket M, one end of which lip is turned up as shown at M in Fig. 6,and the other end of which is turned down as shown at M This bracket Mand the inner lip of the extension P are so related to each other thatwhen the contact maker P is moved toward the right this lip rides overthe top of the bracket M, While when it is moved toward the left, afterhaving been moved to its extreme position against the stop P it slidesunder the lip of the bracket M. When the contact maker P is moved towardthe right and slides over the top of the bracket M, the said contactmaker is raised clear of the pins N and the contact plate 40, but whenit moves in the opposite direction the said con tact maker rides overthe pins N and as it passes down between each pin it touches the contactplate 40; thus when the contact maker P is between the first and secondpins N 1 it points directly toward the figure 1 on the dial and touchesthe plate 40. Passing between 1 and 2 on the dial it rises over thesecond pin and breaks the connection with 40, which connection isrepeated as soon as the contact maker arrives between the second andthird pins and is pointed toward the figure 2 on the dial. Between therow of pins N and the bracket M is another contact strip 51, so arrangedthat when the contact maker is at a position between two pins, if it bepressed downward electrical connection is made between the strip 51 andthe contact maker, and consequently also between the stri 40 and thestrip 51. The contact ma er P is therefore capable of making either asingle or a double contact as is desired, and such contact can be madewhen the contact maker points at any desired figure on the dial N Alsolocated at the central ofiice is a spring jack illustrated by contactsprings 13 and 14 located just above the switch N and the plug V adaptedto be inserted in the said spring jack. Also at the central office thereis a battery X, a bell ringing device Q, receiver R, induction coil K,transmitter T, battery Y, an alternating generator G and contact makingkeys 26, 59 and 78, also a drop magnet 16. These various parts areconnected together by wires as is illustrated.

At each local station there is a direct current generator G, a bellringing device Q, receiver R, induction coil K, receiver hook H, acondenser and magnets A, B, C and D which operate contact making devicesas will be hereinafter described. These different parts are connectedtogether as shown in the dia gram. From the strips of the spring jack atthe central oflice there extend two wires 50 and 100. The wire 50extends past each one of the local telephone stations N0. 1, No. 2, No.3, etc, and is provided with a branch 18 leading to the magnet A of eachstation. The wire 100 terminates in the first station, and

,the second station where it terminates.

From the second station a wire 102 extends to the third station, and soon.

Assuming that subscriber at telephone station No. 1 wants to talk withsubscriber at telephone station No. 3, then he proceeds as follows: Heremoves his receiver R from its hopk and turns the crank of hisgenerator which sends a direct current as follows: G 91O -11ground tothe central office 12-13141516-1750-back to the localstation-1819Q20-21G. This operates the drop at the central office andcalls the operator there. The subscriber presses his listening key andthe central operator inserts the plug V in the spring jack and pressesher listening key 26. The talking circuit between the central office andtelephone station No. -1 is then as follows: beginning at K of the localoflice 22- R23-1918-50to the central oflice 17-2414plug V2526-27-2 8-30-313212ground back to the local.station1133 H3738K. When informed thatthe subscriber at station No. 3 is the one wanted the operator of thecentral office moves the contact maker P to the right to its extremeposition and then returns it to the left, stopping on the way at thenumbers indicated on the dial of the stations that are wanted. Thus thesubscriber at station N o. 1 wanting the subscriber at station No. 3,the operator moves the contact maker until it points at No. 1, thenpresses it downward, then moves it to No. 3, presses it downward again,and then returns it to the left in contact with the contact point 76.After passing over the first pin bl the contact maker P makes a contactwith the strip 40 when a current flows as follows: from battery X-39-40-P25plug V14-241750 to 18 of the first stationA41424344 back to thecentral ofl ice45pl ug V4647X. The current through the magnet A releasesthe spring 42 from the hook on the armature 43 of the magnet A, thusbreaking the circuit through the said magnet at this point, but prior tosuch breaking the armature 43 strikes a contact spring 48 makingelectrical connection therewith and also with a contact point 55. Thespring 48 is in electrical connection with the spring 42 so that thesaid circuit is held through the magnet A until it is broken at theswitch at the central station. When the circuit is broken at thecentralstation the armature 43 falls back against a contact making stop49 and in this position is not in electrical connection with either 42or 48 and consequently the circuit is broken for magnet A at the firststation and is completed from 1.00 to the extension 101 by way of 44, 43and 49'. Then when the contact from this first station a wire 101extends to l maker P passes to the next space there will be a similarcurrent sent from the battery X, eXcept that instead of passing from thebranch 1.8 of the first station it will go to the branch 18 of thesecond station through the magnet A of that station and back over theline 1.01 to 102, following the same previously mentioned course, theresult of which action will be to connect the line 102 with the line 101by way of 49, 43 and 44. By this continued process the connection isextended from station to station for any required distance. Nhen,however, the con tact maker P is pressed down so as to make electricalconnection with the strip 51, as in this case occurs for the firststation and the third station, then for the first station a circuit willflow as follows: (remembering of course that the current is meanwhileheld through the magnet A) X3940P 51 52-12ground to local station11 53-B54*55-484344, where it joins the other circuit through magnet A andreturns over the previous course to the battery X. The current throughmagnet B releases the spring 63 from the hook on the armature lever 73,permitting the said spring to drop back in contact with contact point64. The breaking of the circuit through the magnet B permits thearmature 73 to connect with the contact point 72. The same operationwhich is just described for station N o. 1 is repeated for station No.'3 whereby a current is sent through the magnet B of that station. Inall of the other stations on the party line no current is sent throughthe magnet B, but they are disconnected by the operation of the magnetsA of the respective stations. As the stations on the line are atdifferent distances from the central office, it will be evident that theresistance on the line will be a variable one, and therefore for thepurpose of making the resistance of the current from the battery Xapproximately even, the contact plate is divided up into sections andthe resistance coils 40 which connect them are supposed to represent anamount of resistance equal to the resistance between stations. In thedrawings the resistance is not located at each station contact, but oneresistance coil is put in for each two stations, which will ordinarilybe a near enough approximation to the actual resistance of the line.Thus at station No. 1 which is as sumed to be the nearest to the centraloffice, the current passing from the battery X has to travel all of theresistance coils connecting the sections of the strip 40, whereas atstation N o. 9 there would be no resistance at the central office, andthe total resistance would be the resistance of the line.

To call the subscriber wanted the operator at the central office pressesthe key 59 and turns a generator G, when a current flows as follows:G-565758596025p1ug V14241750 to 18 of the third stati0n19Q-2061H366263646510-249 of the second station43- 44101-49 of the first station4344100-4 5plug' V-4 666676869G. This rings the bell of the third stationand calls the subscriber who removes his receiver. The talking circuitbetween station 1 and station 3 is then as follows: beginning at K ofstation No. 1-22R2319-18 to 18 of station No. 3-1923R 22-K-3837 H- 36626364 65 10249 of station No. 24344101 49 of station No. 1434465646362-36-H37-K. When through talking the subscriber rings off beforereturning the receiver to its hook and from the generator G a directcurrent flows, 9-70 7172737462-63-6465100 45plug V46Q7576-P25-plugV*142417501819Q20*-21 G. This informs the operator at the central oificethat the subscribers are through talking, and the operator presses thekey 78 and turns the crank of a generator which is of the alternatingcurrent type, when a current flows as follows: G56 5777-78 6025plug V-1424175() 18 Of each station1979-C-condenser 80 which does not stop analternating current but does stop a direct currentl 1ground back to thecentral olfice12818283 84 69-G. The current through the magnet C closesthe armature 87 to the contact point 86 at each station when a currentflows as follows: from the battery Z 86-8788D-62Z. The current throughthe magnet D operates its armature on which armature are pins adapted toreturn the springs 42 and 43 to their normal position in contact withthe hooks on the armatures 43 and 73. In this position the devices atall the stations are returned to their normal position.

WVhat I claim is 1. The combination with a central office, a series oflocal stations, and a discontinuous conductor extending from the centralo'llice to the first station and thence from station to station, of twocontact makers at the central oflice, means whereby upon making a seriesof contacts by one of said contact makers the sections of conductorswill be united one by one into a continuous conductor, and means wherebyupon malc'ng a contact with the second contact maker simultaneously witha contact made by the first contact maker the station corresponding tothe section then being united Wlll be telephonically connected to thecontinuous conductor.

2. A telephone selecting switch provided with two contact strips, amovable contact maker, means whereby a movement of said contact maker inone direction will cause it to make a series of contacts with one ofsaid strips, means whereby a pressure upon said contact maker willextend the contact of said contact maker to the other contact strip, andmeans whereby a movement of said contact maker in the opposite directionwill act to prevent said contact maker from making contacts with eitherstrip.

contacts by saidv contact maker the devices of the local stations willbe operated one by one to cut the said local stations out of telephonicconnection with the central station, and means whereby upon making asecond contact while one of the series of contacts is maintainedadditional parts ofthe devices at the corresponding local station willbe operated so as to retain that station in. telephonic connection withthe central station.

4. The combination with a central station, a series of local stations,and conductors connecting the stations, of devices located at thecentral station for making either single or double electrical contacts,means whereby upon making a series of single contacts the local stationswill be excluded one by one from telephonic connection withsaidconductors, and means whereby upon making a double contact in the seriesof contacts the corresponding local station will be placed in telephonicconnection with said conductors. 5. The combination with a centralol'lice, a party line, and a series of local stations, of means by whichupon sending a series of impulses from the central oflice over the partyline, the local stations will be excluded from telephonic connectionwith the line one by one inthe order of the impulses sent, and means bywhich upon sending a secondary impulse with one of the impulses of saidserice, the station corresponding to that impulse will be placed intelephonic connection with the line.

6. The combination with a central o'lli'ce, a series of local stations,and a party line, of two contact makers at the central o'llice, meanswhereby upon making a series of contacts by one of said contact makersthe said ,stations will be selected one by one, and means whereby uponmaking a contact with the second contact maker simultaneously with acontact made by the first contact maker, the station selected at thetime will be telephonically connected to the party line.

7. The combination with a central telephone station, a series of localtelephone stations, and a party line connecting the local stations tothe central station, of a selecting contact maker located at the centralstation and capable of making either single or double electricalcontacts, means I whereby upon making a series of single electricalcontacts with said contact maker each such contact will cut out acorresponding local station from telephonic connection with saidpartyline, and means whereby the making of a double electrical contact withsaid contact maker each such double contact will bring a 9. Thecombination with a central office, a

series of'local stations, and a party line, of a calling device locatedat the central oflice and arranged to make either single or doubleelectrical contacts for the stations in succession, means by which eachstation for which a single electrical contact is made will be excludedfrom telephonic connection with the party line, and means by which eachstation for which a double electrical contact is made will be placed intelephonic connection with the party line.

1.0. The combination with a party line, a

. series of local stations, means for sending a series of impulses overthe line, and means for associating a second impulse with any oneimpulse of said series, of devices at each station operated by saidimpulses, means by which upon sending such series of impulses saiddevices will be operated so as to exclude the stations from telephonicconnection with the line one by one in the order of the impulses sent,and means by which upon sending an extra impulse with any one of theseries of impulses the devices of the corresponding station will beoperated so as to place that station in telephonic connection with theparty line.

11. The combination with a party line, and a series of local stations,of means by which upon sending a series of impulses over the party linecorresponding in number to the number of stations each impulse in itsorder will cause the corresponding station to be cut oil from telephonicconnection with the line, and means by which upon coupling a secondaryimpulse with any one impulse of the series of impulses the stationcorresponding to that impulse will be placed in telephonic connectionwith the line.

12. The combination with a series of sta- TIO tions, and a party line,of a magnet at each I so as to exclude all contacts made by thesubscribers at their stations, means for connecting said circuitssuccessively and temporarily to said line, and means for sendingimpulses through a plurality of selected ones of said circuits at thetimes when they are temporarily connected to said line whereby themagnets in said circuits are operated to connect desiredstationstelephonically to the party line.

13. The combination with a party line, and a series of local stationseach potentially capable of being telephonically connected to the line,of means by which upon sending a series of impulses overthe linecorresponding to the stations thereon each impulse in its order will cutof]? the capability of the corresponding station to be telephonicallyconnected to the line, and means by which upon sending a secondaryimpulse with any 1mpulse of the series of impulses the stationcorresponding to the selected impulse will be telephonically connectedto the line.

Signed at Chicago, Ill. this 28th day of March 1901.

N. EMEL NORSTROM.

Witnesses CHAS. O. HAToH, WILLIAM M. RoBERTs.

